Screening of molecular libraries in the pharmaceutical and personal care industries often results in the generation of large numbers of lead compounds. This, in turn, has resulted in a need for new high-throughput methods of screening these compounds for potential toxicity prior to conducting human clinical trials. The goal of the present proposal is to develop a skin model and associated methodology to allow high- throughput testing of topically applied pharmaceuticals or other materials by monitoring gene messages related to a broad variety of dermal phenomena. The model will be composed of three-dimensional organotypic human skin cultures in a 96-well format. Culturing at the air/liquid interface and in-vivo-like barrier properties will enable new pharmaceuticals and/or finished products to be tested in a topical, realistic manner. RNA will be extracted from the tissues and specifically quantified in a 96-format by means of engineered capture and detection probes. During Phase I, the utility of this methodology will be demonstrated by preparing and testing probes for p53 (genotoxicity), IL-1alpha (irritation), and beta-actin (control) message. The tissue model and methods should be adaptable to enable investigation of message modulation for any gene of interest provided appropriate probes can be engineered. The methods will be adapted to other tissue models and gene messages in Phase II. PROPOSED COMMERCIAL APPLICATIONS: The proposed high-throughput skin model will find application in product safety assessment for a broad variety of pharmaceutical, chemical, and consumer product companies who engage in high-throughput screening to identify lead candidates, and whose products may be intended for topical use. The model will also be adaptable for other basic studies involving modulation of gene messages in skin by chemicals, UV radiation, or other exogenous treatments.